Data and Metadata

The 5800 system stores two types of data: arbitrary
object data and structured metadata records.
Every metadata record is associated with exactly one data object.
Every data object has at least one metadata record. A unique object
identifier (OID) is returned when a metadata record is stored. The
OID can later be used to retrieve the metadata record or its object
data. In addition, metadata records can be retrieved by a query:

OID ↔ Metadata Record -> Object Data

The two types of metadata are system metadata and user metadata. The names and types of system metadata
are predefined and cannot be overridden by the user.